Traffic signal



A ril 6, 1937. E 2,076,396

TRAFFIC S IGNAL Filed Oct. 4, 1928 2 Sheets-Sheet l INVENTOR.

ATTORNEY.

April 6, 1937. A. A. BLUE TRAFFIC SIGNAL 2 Sheets-Sheet 2 MW K Filed 001;. 4, 1928 INVENTOR Patented Apr. 6, 1937 UNITED STATES PATENT OFFICE TRAFFIC SIGNAL Application October 4,

24 Claims.

This invention relates to signals, and more particularly to traffic signals of the kind generally employed at street intersections for directing and regulating the movement of trafiic across the intersection.

Such systems ordinarily are provided with one or more series of lights, each series having three lamps, one of which is red, one yellow, and one green. Frequently there are two such series of lamps, one for controlling north and south traflic, and the other for controlling east and west traffic.

In the following specification, I will describe my invention with particular reference to a system wherein there are at least two such series of lamps, but it will be understood that the invention is equally applicable to a system employing one or more series of lamps, as sometimes only a single series of lamps is used with properly arranged colored lenses.

In systems of this kind, as now generally provided, there is a motor-driven switch which operates at uniform speed for periodically closing the circuits to the respective lamps, the arrangement being such that when there is a green light for north and south traffic, there is a red light for east and west trafiic, and vice versa. There is ordinarily a time interval when the lights are changing from red to green, in which a yellow lamp is lit for traffic approaching in all directions. With such systems, the switch for controlling the lamps operates at a continuously uniform speed, and at the end of a predetermined period the signals will change. For instance, after they show green for east and west traffic for a given period, they will change at the end of the time interval to show green for north and south traffic and red for east and west trafiic. The lights will remain this way until a predetermined time interval has elapsed, whether there be any trafiic going in the north and south direction or not. This means that east and west trafiic is being held up, although there may be no traffic moving north and south at all. In the same way, north and south traflic may be held up for the full time interval, although there be no east and west traffic at all.

According to the present invention, there is provided a system wherein the switch for controlling the lamps will normally operate at a uniform speed, but wherein there will be a selective operation of the switch at a non-uniform speed where a vehicle is being held up from travel in one direction, and there is no traffic in the other direction. For example, the arrangement is such that if a green light is showing for north and south traific, and a red light for east and 1928, Serial No. 310,263

west trafiic, and there are no vehicles traveling in a north and south direction, the switch mechanism will be accelerated by the approach of a Vehicle in the east or west direction, so as to more quickly flash a green light in the east and west direction.

The arrangement further contemplates a mechanism wherein such acceleration of the movement of the switching means will not take place if a Vehicle, in the example above given, should approach in a north or south direction. In other words, as long as there is trafiic in each direction, the movement of the switch will be uniform, and acceleration will only take place where traffic is held up in one direction and there is no trafiic in the other direction.

The arrangement may be readily understood by reference to the accompanying drawings, which illustrate an embodiment of my invention and in which:

Fig. 1 is a schematic view showing a crossing, crossing light signals, and a circuit for the crossing light signals, including means for selectively imparting a non-uniform movement to the light operating switch;

Fig. 2 is a diagrammatic view showing one form of vehicle-controlled detector which may be used in the system outlined in Fig. 1;

Fig. 3 is a detail perspective View of one of the switches;

Fig. 4 is a diagram showing a modified circuit for the detectors; and

Fig. 5 is a developed view of the light operating switch of Fig. 1.

In Fig. 1 E-W designates an east and west traffic lane, and NS designates a north and south trafiic lane, the two intersecting. Located some distance back from the intersection at each of the four corners, and arranged so as to be operated only by a vehicle approaching one of the. corners, are detecting devices I, 2, 3 and 4. Detector I is adapted to be operated by traffic approaching from the east, and 2 by trafiic approaching from the west. Detector 3 is arranged to be operated by traffic approaching from the north, and No. 4 is to be operated by trafiic approaching from the south.

As most clearly indicated in Fig. 2, each detector comprises a stationary contact member 5 and a movable contact member 6. The member 6 is adapted to make circuit with the contact 5 by the passage of a vehicle in the range of the detector. For instance, a movable plate 1 may be mounted in the roadway adapted to be pressed down by the passage of a vehicle thereover, and

this plate in moving down will force the circuitclosing member 6 into engagement with the contact to complete a circuit, as hereinafter more fully described.

5 In place of the detector arrangement shown, any suitable arrangement for making a circuit by the passage of a vehicle may be substituted. As an example, the vehicle might be made to interrupt a beam of light or other radiant energy falling onto a photo-electric cell or other radiant energy responsive means and through response of such cell or other means close a relay to complete the circuit hereinafter described.

Also, a microphone or like sound responsive device can be disposed in position to produce the closing of circuit upon sounding of a horn on the Vehicle, as will be understood by those skilled in the art and not considered necessary to illustrate here.

At 9 there is shown a series of three lamps R, Y and G for directing north and south traflic and at I0 is a similar series of lights R, Y' and G for regulating east and west trafiic, the letters R, Y and G standing for red, yellow and green, (conventionally representing stop, caution and go), respectively. One side of each of the lamps in each series is connected to one side of a power supply line II. At I2 is a revolving drum switch having contact plates, 7', y and g thereon, the plate y having a duplicate part (shown only in Fig. 5)

on the diametrically opposite side of the drum. Lamps R, Y and G each have a wire 1", y and g terminating in a contact brush adapted to make circuit at the proper time with the contact plates r, y and g, respectively, of the switch I2. Similarly, the lamps R, Y and G are connected through wires r 1/ and g respectively, with brushes that are also arranged to contact at the proper time with contact plates r, y and 9, re-

spectively. The contact plates 1, y and g are connected with the other line I3 of the current supply.

With the arrangement shown in Fig. 1, the circuit is closed at the same time through lamp R, through lamp G, thereby showing go for east and west traffic, and showing stop for north and south traffic. As the switch I2 revolves, lights Y and Y will be lighted at the same time, and then upon further rotation of the switch I2, lamps G and R will be simultaneously lighted. As a result of the arrangement just described, rotation ot the switch I2 will effect a cycle of signal displays which, for convenience in description, will be assumed to start with the lighting of the lamps R and G when the switch I2 is positioned as shown, so that the plate 1' connects with conductor 1 and the plate 91 connects with conductor 9 Thereafter, intended rotation of the switch I2 will carry the plates 1/, 1 into connection with conductors y, 111 thus causing the lighting of lamps Y and Y; and, at or about the same time, the plates 1' and y will be withdrawn from connection with conductor r and 9 respectively, thereby causing extinguishment of the lamps R and G. During subsequent rotation of the switch I2, when the lamps Y, Y have been lighted for desired time, the plates 1' and y will be carried into connection with the conductors r and g, respectively, thus causing the lighting of lamps R and G; and, at or about the same time, the plates y, y will be withdrawn from connection with the conductors y, 11 and thereby causing extinguishment of the lamps Y, Y. Subsequent rotation of the switch I2 will next bring the plates y, :1; into connection with conductors y, 11 and thereby cause relighting of the lamps Y, Y; and, at or about the same time, the plates 9 and T will be withdrawn from connection with the conductors g and r respectively, thereby causing extinguishment of the lamps G and R. The rotation of the switch I2 will next return the parts to the position first described, where the plates g and r connect with the conductors g and r, respectively, causing the lighting of the lamps G and R; and the plates y, y are withdrawn from connection with the conductors y, g so that the lamps Y, Y will be extinguished. The switch I2 is continuously rotated in any suitable manner by a motor I4. One side of the motor I 4 is connected directly with the current supply line I3 through wire I5. Connected to the other side of the motor is a wire I6. Wire I6 is in series with a resistance I1, and on the other side of the resistance I1 is a contact I8. At I9 is a switch which is normally held against the contact I8 by means of a spring 20, and the switch I9 is connected through wire 2I with the other side of the current supply I I. The motor I4 is, therefore, normally supplied with current which passes through the resistance I'I, whereby the motor I4 normally operates at slow speed. Shunted around the resistance I1 is a wire 22 terminating in a contact 23. The switch plate I9 may be moved out of engagement with the contact I8 into engagement with the contact 23. When the switch I9 is in contact with the contact 23, the resistance I! is cut out of the circuit and the motor will operate at a much higher speed. For actuating the switch I9, I have shown an electro-magnet 24. One side of the electro-magnet 24 is connected to the line I3 through wire 25. Connected to the other side of the electro-magnet 24 is a wire 26. The wire 26 divides into two branches 26' and 26*, each of which terminates in a brush 26 and 26 adapted to make contact with a contact plate 2'! on a rotating switch member 28. The switch member 28 may be rotated in either direction by a reversible torque motor 29, and the switch 28 will be returned to its normal position, shown in Fig. 1, by a spring 30, upon deenergization of the motor 29.

At 3| there is a movable switch member in the form shown in Fig. 3 comprising a cylinder of insulating material adapted to rotate on its axis indicated by a shaft 32 and having contacts thereon as hereinafter described. This switch member has an arm 33 projecting downwardly from one end thereof. Secured to the member 33 is an armature 34, which enters solenoids 35 and 36 located at opposite sides of the extension 33. The arm may be weighted to cause it to hang in a normal vertical position.

The one side of the solenoid 35 is in a circuit which includes the line wire II, wire 37, detectors 3 and 4, wire 38, contact plate 39 on the switch 3| and wire 49. The other side of the solenoid 35 is connected through wire 4| with switch contact brush 43 adapted to contact with switch segment 42 also on the switch I2. The circuit is completed from segment 42 through wire 64 to the other side of the power circuit I3.

One side of the solenoid 36 is connected with the current supply line I I through wire 31, detectors I and 2, wire 46, contact plate 41 on the movable switch member 3|, and wire 48. The circuit is completed from the other side of the solenoid 36 through wire 49, contact brush 49 adapted to engage segment 42 upon rotation of the switch I2, and from segment 42 through wire 64 to line wire I3.

At 50 is a ratchet-like latch which is normally held in an operative position by a spring and which can be rocked downwardly to an inoperative position by means of an electro-magnet 52. Opposite the latch 59 is .a similar latch 50' having a spring 5| and an actuating magnet 52'. The arrangement is such that when the solenoid 35 is energized to rock the switch 3| on its pivot 32 in one direction, the extension 33 thereof will ride over the catch or latch element 56 to retain the switch in the position to which it is moved until such time as the magnet 52 is energized to release the latch 50 .and permit the switch to return to its normal position. The latch 50 operates in a similar manner when the solenoid 36 is energized to move the switch 3| in the opposite direction. The circuit for the electromagnets 52 and 52' leads from line H through wire 53, magnet 52, wire 54, magnet 55 of an electrically-opened switch 56, wire 51, magnet 58 for a switch 59 similar to switch 56, wire 69, magnet coil 52, wire 6| and contact brush 62. Carried on the revolving switch l2 are contact plates 63, 63 (see also Fig. 5) which are adapted to be brought by rotation of the switch |2 into engagement with contact brush 62, thereby completing a circuit through wire 64 back to the other side of the power circuit |3. With this arrangement, it is assured that with movements of the switch |2 for effecting changes in the display of signals from go to stop and from stop to go or with other predetermined movements of said switch l2, the latches 50 and 50 will be released. At the same time, the switches 56 and 59 hereinafter described are momentarily opened by the energization of magnets 55 and 58.

One side of the reversible motor 29 connects with one side of the power line I through wire 65. For driving the switch 28 in one direction, the motor 29 is connected with the other side of the source of power through a wire 66, electro-magnetically opened switch 61, wire 68, electro-magnetically opened switch 59, wire 63 and contact brush 10. The contact brush I0 is adapted upon operation of the switch 3| by the solenoid 35 to make contact with contact plate H on the switch 3|. Plate 1| is connected through wire 12 with the power circuit |3. For driving the motor 29 and the switch 28 in the reverse direction, the motor circuit includes wire 13, switch 14, similar to switch 61, wire 15, switch 56, and contact brush 16. Contact brush T6 is adapted to close the circuit through contact plate H on switch 3| when the switch 3| is operated by energization of solenoid 36. On the switch 3| is a contact plate 80 which is adapted to contact with contact members 38 and 8|) when the switch 3| is operated by the solenoid 36. Contact member 8|] is connected through wire 8| to contact plate 82 on the reversible switch 28. At 83 is a brush adapted to make circuit with the plate 82, this brush being connected through a wire 84 with a magnet coil 85 for opening switch 14. From the magnet 85 the circuit is completed through wire 45 to the power line I3. On the switch 3| is a plate 81 similar in purpose to plate 80 adapted to make contact upon movement of the switch toward the left in Fig. l with brushes 4|? and 81 The contact member 81 is connected by a wire 88 to a plate 89 on the reversible switch 28. Plate 89 is adapted to contact with brush 90. Leading from the brush 96 is a wire 3| connected to one side of magnet coil 92 for opening the switch 61. From the other side of the magnet 92 is a wire 93 which connects back to line |3 through conductor 45.

With this description of the arrangement of the circuit, the operation may now be traced. Assum'e trafiic is open in the EW direction, and closed in the NS direction, due to the position of the switch l2 at a given moment, and a car approaches on the N-S roadway with no traffic on the E-W route. By means of one of the detecting elements 3 or 4, the approaching car causes a current to pass from brush 38 of switch 3| then in contact with segment 39 to the wire 40, through the solenoid 35, wire 4|, contact segment 42 on switch I2 and wire 64 to the other side of the power circuit l3. The energization of the solenoid 35 acts upon armature 34 to rock the switch 3| about the pivot 32, and causing the extension 33 of the switch to be engaged by the latch 50. When the upper part of the switch 3| is thrown to the left, as viewed in Fig. 1 by the operation of the solenoid 35, segment H on the switch moves into contact with brush 10, closing the circuit through wire 69, switch 59, wire 68, switch 61, wire 66 to motor 29, and from motor 29, through wire 65 to line H. When the motor 29 is thus energized it starts to rotate the switch 28, moving contact plate 21 thereon, which contact plate 21 is connected with line H through wire 21 into contact with brush 26 A circuit is then completed through wire 26 wire 26, electro-magnet 24, wire 25, back to the other side l3 of the power circuit. This energization of the electro-magnet 24 moves the switch |9 from contact 8 to contact 23, thereby shunting the resistance I! of the motor l4, speeding the driving motor up to more rapidly rotate the switch 2. As soon as the switch 2 has rotated farenough to make contact on the intermediate zone y of the switch |2, one of the segments 63 on the switch |2 will be in contact with brush 62. A circuit will then be closed through the magnet 52', magnet 58, magnet 55 and magnet 52. The energization of the magnets 52 and 52' releases both the latches 50 and 50', and since the switch 3| is being held over by the latch 59, the switch will be released in the example assumed upon energization of the magnet 52. At the same time, both switches 56 and 59 will be opened by the energization of magnets 55 and 58, thereby breaking the circuit to the reversible motor 29. Upon deenergization of the motor 29 the spring 36 rotates the switch 28 back to neutral position.

It will be evident from the foregoing that in the instance assumed, the car approaching on the closed N-S roadway will thus control the speeding up of the motor M to effect a quick change of signals. A car approaching on the E-W roadway at this time will cause none of the mechanism herein described to operate because no circuit can be completed from the solenoid 36 through the wire 49 to the contact plate 42 on the switch I2, the plate 42 being located to close circuit with the green light positions of switch l2. Contacts 63, 63 are coordinated with the yellow light segments 1 of the switch l2.

Assume that shortly after the car approaches in a N--S direction, as just described, another car comes along the EW roadway where the alternating signal already shows green, and where normally the right of way should be on a time basis. It will be noted that after the motor 29 starts to operate, a time interval elapses before the contact plate 21 makes contact with either of the brushes 26 or 26 This space, and the speed of the motor can be adjusted as may be desired to secure a suitable time interval before the speeding up of the motor I4 is secured. If this second car, coming in the EW direction, arrives before this time interval has passed, it operates one of the detectors I or 2, causing a current to pass through wire 46, brush 46 contact plate 81, contact member 81 wire 08, contact segment 89, brush 90, magnet 92, and back to line I3 through wire 45. The energization of the magnet 92 opens the switch 61 temporarily breaking the current to the motor 29. It will be understood that brush ll-i will contact with plate 81 because of the switch 3| at that time being rocked to the left of the position shown in Fig. 1. Upon opening of the switch 61 to deenergize the motor 29, the spring 30 returns the switch 28 to the normal position. As soon as the car on the EW highway has passed the switch 61 will be closed, and again the motor 29 starts to turn the switch 28. This is repeated until no cars on the EW highway interrupt the action, or until the switch I2 has moved in the course of its normal operation to a position where it opens all of the circuits previously described. It will be noted that a car coming in the EW direction does not restore the circuit to normal. In other words, after a detector operates, its operation registers in the actuation of one of the solenoids, 35-30 and the effect thereof, while it may be retarded, is not negatived by a passage of a car in the open direction.

If a car on the EW highway approaches after the time interval has passed for the segment 2! to close the circuit with brush 26 it has no effect on the action, due to the fact that the segment 21 having reached a point of contact with brush 20 the rotation of the switch 28 has carried segment 89 out of contact with brush 90. By this time the switch I2 would have revolved suificiently to flash red in the EW direction and green in the N-S direction. With the changing of the lights, the various circuits are restored to normal, as previously described. While the lights show green for the NS direction, the condition is just the reverse of that described when the light is green for the EW direction, and the same operation will take place when a car approaches on the EW roadway, the solenoid 36 in this instance being energized instead of the solenoid 35, so that switch 3I is moved to the right, as viewed in Fig. 1, instead of the left, and this results in the motor 29 revolving to the right instead of to the left, as Viewed in Fig. 1.

It will be seen that the invention results in an arrangement wherein the alternating time signal is caused to operate preferentially, except when the interval between cars is not great enough to justify a change in traffic flow for vehicles waiting in an intersecting direction.

When it is desired to have a detecting device which will respond only to vehicles approaching the intersection, and not those leaving it which is desirable when the detecting devices are in such positions as to be likely to be subject to unintended operation by traffic which is moving away from the intersection, the arrangement shown in Fig. 4 may be used in combination with the apparatus hereinbefore described. In this arrangement, there is provided a rotary switch I and a similar switch ml. The switch I00 is of the general construction of the switch 3| shown in 7 Fig. 3, but carries a single contact plate I02. The

switch is rotated by means of an arm I03 having a weighted armature I 04 thereon adapted to be attracted by the electro-magnet I05. At I06 is a latch similar to the latch 50 previously described, adapted to cooperate with the end of the arm I03 for holding the cylinder I00 in the circuit-closing position after it has been moved to this position by the electro-magnet I05. An electro-magnet I0'I is provided for releasing the latch I06.

Switch I00 is for the north and south detectors, and switch IOI is for the east and west detectors. Two detectors are placed on each of the intersecting directions at suitable distances apart, not less than the length of an average vehicle. The first detectors I08 in the north and south direction are connected in parallel, one side of each detector being connected to a source of power through wires I09 and I I0. The wire IIO terminates in a brush III adapted to make circuit with contact plate I I2 provided on the rotating switch I2 in addition to the contact plates hereinbefore described. The plate H2 is connected through wire I I3 to one side of the power supply circuit. The other sides of the detectors I08 are connected to wire I I4 which connects to wire I I5 connected to one end of the electro-magnet I05. The other end of the electro-magnet I05 connects to the other side of the power supply circuit through wire II6.

When a vehicle actuates either of the detectors I08, a circuit is closed through the electromagnet I05 and the switch I00 actuated. The actuation of the switch I00 moves the plate I02 into contact with a brush Ill. The second detectors II8 are connected in parallel. One side of each of the detectors H8 is connected to the brush Ill through the wire I I9. The other sides of the two detectors IIB are connected by a wire 9 Connected to wire H9 is a wire I20 corre sponding to the wire 38 of Fig. 1. The contact plate I02 is connected to the other side of the source of power, there being a wire I2I leading to the other side of the source of power.

After the switch I00 has been rotated, as previously described, the plate I02 connects the detectors II8 into an operative circuit. With the switch in the position shown in Fig. 4, the inside detectors IIB are not in an operative circuit.

In operation, a car may be assumed to be approaching the intersection from the north, the signal being clear to east-west trafiic. It first actuates the detector I08 to rotate the switch I 00, thereby connecting the detector H8 in an operative circuit. When the vehicle approaches the second detector II8 it operates this detector and causes the apparatus described in connection with Fig. 1 to function just the same as the detectors 3 or 4 of Fig. 1 cause it to function. The effect of operating the detector H3 is to accelerate the changing of the signal so that the vehicle can proceed. Just as soon as the switch I2 rotates to change the signal, the circuit through plate I I2 and contact III is broken. At the same time, another contact plate I22 on the switch I2 having one side thereof connected to the source of power through wire II3 makes contact with a brush I23 and closes a circuit including wire I20 through the electro-magnets I01 and I01 back to the source of power through wire I25. This energizing of the electro-magnet I0I releases the latch I06 and allows the switch I00 to return under action of the weighted arm I03 to the position shown in Fig. 4, whereupon the circuit through wire H9 to the inner detectors H8 is broken. Although the vehicle might operate the detector H8, when leaving the intersection, such detector would not, upon such an occasion, be in an operative circuit. Hence there would be no significant response to such operation of the detector H8. Thus it will be seen that the inner detectors l l 8 will not function to control the signal unless one of the outer detectors I08 is first operated. A vehicle leaving the intersection will therefore have no effect, the signal being operated entirely by one approaching the intersection. This arrangement can be provided in lieu of having detectors at the side of the road, as indicated in the arrangement shown in Fig. 1, wherein each detector is in one line of trafiic only.

The switch I] is in all respects similar to the switch I 00 and the circuits correspond to the circuit for the switch I00. For convenience, the reference numerals applied to the switch IOI are the same as those used on the switch lllll, except that the prime mark has been affixed thereto to correspond to reference numerals.

While I have shown a specific embodiment wherein the signal is changed by means of a rotating motor-driven switch, it will be understood that the invention is not confined'to the particular arrangement shown, and various other means, such as brakes, clutches, gears or the like may be used for varying the motor speed, instead of the shunting of a resistance, as shown. It will also be understood that the invention is not limited to an arrangement wherein the switch is necessarily operated by an electric motor, but includes any system wherein an alternating traffic light is operated in preference by the vehicles, except where the trafiic in each direction is such as to justify the regular periodic changing of the lights.

I claim:

1. The combination with intersecting roadways, of stop-go traffic signals for alternate display at the intersecting roadways, automatic switch means periodically changing the signals at normal regular intervals, a traffic detector in each roadway in advance of the intersection, control means for said automatic switch means operable by response of a selected trailic detector in one roadway for accelerating the operation of said switch means upon the approach of a vehicle to the intersection, selector means operating with said switch means and operative to place said control means for said switch means under successive control of said tr'afiic detectors so that the operation of a traflic detector in the roadway having the stop signal at a given instant will tend to accelerate the operation of the switch means, and means controlled by non-selected traific detectors for preventing the operation of said control means and cooperating with said control means so that acceleration of the traffic-controlled means by traflic on the roadway having at a given instant a stop signal will not accelerate the operation of the switch means if the trafiic detector in the other roadway is operated before the signal is changed.

2. The combination with a road intersection, of an alternating stop and go traffic signal and switch means operative in recurrent cycles having a normal period to periodically change the signal at normally regular intervals, said signal being adapted to give a stop indication along one of the intersecting roadways at the same time that it indicates go along the other of the intersecting roadways, vehicle-controlled means for temporarily shortening the normal operating period of the switch means, and means for effecting restoration of the normal period of the operation of said switch means with each cycle thereof.

3. The combination with a road intersection, of a stop and go traffic signal and switch means having a normal operating period for changing the signal at normally regular intervals, said signal being adapted to give a stop indication along one of the intersecting roadways at the same time that it gives a go indication along the other of the intersecting roadways, vehicle-controlled means temporarily shortening the normal operating period of the switch means, and other traffic-controlled means preventing the shortening of the normal operating period of the switch means, said arrangement being characterized by the provision of a means whereby only traffic which approaches the signal in the direction in which a stop is indicated can shorten the. normal operating period, and further characterized by the provision of means wherein only a vehicle approaching in the direction in which the signal indicates go can prevent such shortening of the normal operating period, said arrangement being further characterized by the provision of means for restoring the signal to normal operation with each change of the signal.

4. A trafiic signaling system for interfering traflic lanes having means presenting right-ofway signal indications, signal control means normally cyclically presenting said right-of-way indications successively to the several trafiic lanes, a vehicle controlled means for temporarily accelerating the cycle of the signal control means, and other vehicle controlled means for retarding the function of said first vehicle controlled means.

5. In a traffic signaling system for,interfering trailic lanes having means presenting right-ofway signal indications, signal control means normally cyclically presenting said right-of-way indications successively to the several trafiic lanes, a vehicle responsive detector in each lane in advance of the intersection, means governed by the operation of the detector in one lane for temporarily accelerating the cycle of the switch signal control means, means governed by and responsive to the frequency of operation of the detector in another lane. for retarding the accelerating function of said accelerating means, and means operating with the signal control means for alternately connecting the detector of each lane for control of the accelerating means and then of the retarding means.

6. In a trafiic signaling system for interfering roadways having means presenting right-of-way signal indications, signal control means normally cyclically presenting said right-of-Way indications successively to the several roadways, trafiic detectors located in the roadways in advance of the intersection, means governed by said detectors and operable for temporarily accelerating the cycle of the signal control means, means governed by said detectors and operable for temporarily retarding the operation of said accelerating means, and means for alternately and separately connecting said detectors of the several roadways for control of said accelerating means and said retarding means.

7. In a system for controlling trafiic at highway intersections, a signal for approaching vehicles on each highway including clear and stop indications, constantly operating timing means operative regardless of trafiic conditions for controlling said signals whereby said timing means operates through successive cycles during which the signal for one highway changes from the stop indication to clear and then back to stop while the signal for the other highway changes from the clear indication to stop and then back to clear, and means influenced by the approach of a vehicle on one highway for automatically reducing the time of operation of said timing means for reducing the period of operation of the clear indi- 10 cation for the other highway.

8. In a system for controlling traific at highway intersections, a signal for approaching vehicles on each highway including clear and stop indications, motor driven timer means operative regardless of trafiic conditions for controlling said signals whereby said timing means operates through successive cycles during which the signal for one highway changes from the stop indication to clear and then back to stop while the signal for the other highway changes from the clear indication to stop and then back to clear, and means influenced by the approach of a vehicle in one highway when the clear indication is in operation for the other highway for accelerating the speed of operation of the motor of said timer means.

9. In a system for controlling trafiic at highway intersections, a signal for approaching vehicles on each highway including clear and stop indications, timing means for controlling said signals whereby said timing means operates through successive cycles during which the signal for one highway changes from the stop indication to clear and then back to stop while the signal for the other highway changes from the clear indication to stop and then back to clear, a shaft for operating said timing means, a motor constantly energized for rotating said shaft, and means influenced by the approach of a vehicle on one highway for increasing the speed of rotation of the motor while the clear indication is in operation on the other highway.

10. In a system for controlling highway traffic at highway intersections, a signal for approaching vehicles on each highway including right-of-way and stop indications, timing means for controlling said indications to transfer the right of way back and forth between said highways, a shaft for operating said timing means, a motor constantly energized for rotating said shaft, electrical means normally arranged in the circuit of said motor for retarding the speed thereof when the right-ofway indication is in operation on one highway, and means rendered operative by the approach of a vehicle on the other highway for rendering said electrical means inoperative whereby the speed of said motor will be accelerated when the rightof-way indication is in operation for the first named highway.

11. In traffic signal system for interfering 6O traffic lanes having means presenting right-ofway signal indications, signal control means including a continuously moving signal control device operative at a normal rate to cyclically present said right-of-way indications successively to the several traffic lanes, a trafiic responsive device associated with one of said lanes, and control means operative by response of said traflic responsive device to increase the rate of movement of said continuously moving signal control device.

70 12. In a traffic signal system as defined in claim 11, said signal control means including a continuously rotating motor for continuously moving said signal control device and wherein said control means is operable by response of said trafiic re- 75 sponsive device for temporarily increasing the speed of said motor to increase the rate of movement of said signal control device.

13. In a traffic signaling system as defined in claim 11, the combination therewith of a second traffic responsive device in a second traific lane, and control means operable by response of said second traffic responsive device to render inoperative said control means responsive to said first tramc responsive device.

14. In a traffic signal system for interfering traffic lanes having means presenting right-ofway signal indications, signal control means including a continuously moving signal control device operative at a normal rate to cyclically present said right-of-way indications successively to the several trafiic lanes, a trafiic responsive device associated with one of said lanes, and control means operative by response of said traific responsive device for temporarily accelerating the rate of movement of said signal control means.

15. In a traffic signaling system for interfering traflic lanes having means presenting right-ofway signal indications, signal control means normally operable to cyclically present said right-ofway indications successively to the several traflic lanes, a traffic responsive device associated with one of said lanes, acceleration control means controlled and operable by response of a traffic responsive device associated with one lane to accelerate the operation of said signal control means to shorten the current cycle, and means controlled and operable by sufficiently frequent response of a traffic responsive device in the lane having the right-of-way for temporarily interrupting the operability of said acceleration control means.

16. In a trafiic signaling system for interfering traffic lanes having means presenting right-ofway signal indications, signal control means cyclically presenting said right-of-way indications successively to the several trafiic lanes and including signal control mechanism and motor means operating said signal control mechanism, trafilc responsive devices associated with said several lanes, motor control means operable for varying the speed of operation of said motor means to vary the cycle of signal presentation, switch means operable governed by the response of a traiiic responsive device associated with a lane not having the right-of-way for controlling the operation of said motor control means, switch means operating with said signal control means for successively placing said trafiic responsive devices in control of said first named switch means, and means operable governed by response of a traffic responsive device in the lane having the right-of-way for temporarily interrupting the operability of the motor control means during its operation.

1'7. In a traffic signaling system for interfering trafiio lanes having means presenting right-ofway signal indications, signal control means including a constantly driven motor cyclically presenting said right-of-way indications successively to the several traffic lanes, trafiic responsive devices in the several lanes, control means operable governed by response of said devices to vary the speed of said motor, and means operable governed by response of a second traific responsive device in one lane within a predetermined time period following the response of a first traffic responsive device in another lane for preventing the operation of said control means.

18. In a trafiic signaling system for interfering traffic lanes having means presenting right-ofway signal indications, signal control means iii cyclically presenting said right-of-way indications successively to the several traffic lanes, a traffic responsive device associated with each of said traffic lanes, control means operable by response of said trafiic responsive devices to hasten the cycle of said signal control means when there is approaching traific on a lane that does not have the right-of-way and insufiicient traffic on the lane that has the right-of-way, means also operable by response of said trafiic control devices tending to interrupt the operation of said control means, when there is suflicient traflic on the lane that has the right-of-way, and means alternately placing said trafiic responsive devices in control of said cycle hastening control means and said interrupting means.

19. In a traffic signaling system for interfering traffic lanes having means presenting stop-go signals, signal control means including a constantly driven motor cyclically presenting sa d stop-go signals successively to the several traffic lanes, traffic responsive devices associated with said means, and control means operable by response of a traflic responsive device, in a stop lane only, to increase the speed of said motor,

and means operable by response of a trafiic responsive device on a go lane for hindering the operation of said acceleration control means.

26. In a trafilc signaling system for interfering traific lanes having means presenting right-ofway signal indications, switch means for effecting presentation of said right-of-way indications successively to the several traffic lanes, motor means which operates said switch means at a normal rate, means operable to modify the rate of operation of said motor means to change the rate of operation of said switch means, traffic responsive devices in the several lanes, means operable by response of a selected trafiic responsive device to effect the operation of said rat-e modifying means, means operative synchronously with said switch means to select a particular trafiic responsive means to effect the control of said rate modifying means, means operative to hinder the operation of said rate modifying means, and means operable by response of a selected one of said traffic responsive devices for rendering said hindering means responsive to the operation of another of said traffic responsive devices.

21. In a traffic signal system for interfering tramc lanes having means presenting right-ofway signal indications, a signal device, when operative, to display the signals progressively to the several lanes, a timing device in control of said signal device and constantly operating the same to determine the normal period of signal presentation on any lane and having means, when conditioned, providing signal presentations of shorter durations than such periods, trailic responsive means associated with certain of said lanes, means operative by response of a traffic responsive means associated with a lane that does not have a right-of-way signal displayed thereon for conditioning said timing means for a shorter than normal period duration of signal presentation on the lane on which the signal is set at the time of response of said traffic responsive means, and means responsive to the change of signal presentation to restore said timing means to the normal period duration of signal presentation.

22. In a traffic signal system for interfering traffic lanes having means presenting right-of- Way signal indications, a signal device, when operative, to display the signals progressively to the several lanes, a timing device in control of said signal device and constantly operating the same to determine the normal period of signal presentation on any lane and having means when conditioned, providing signal presentations of shorter durations than such periods, trafiic responsive means associated with certain of said lanes, means operative by response of a traffic responsive means associated with a lane that does not have a right-of-way signal displayed thereon for conditioning said timing means for a shorter than normal period of signal presentation on the lane on which the signal is set at the time of response of said traffic responsive means, means operable by response to traffic on a lane having a right-of-way signal displayed thereon for preventing the shortening of the normal period of signal display, and means responsive to the change of signal presentation to restore said timing means to the normal period of signal presentation.

23. In a traffic signaling system for interfering traflic lanes, means for concurrently displaying a go signal to one lane. and a stop signal to another lane, means for operating said signal display, means to effect periodic display of said signals to the several lanes in an irrevertible progressive manner under all conditions of traffic on said lanes, means operable in response to trafiic on a lane having the stop signal displayed thereon for hastening the progression, and means operable in response to traffic on a lane having the go signal displayed thereon for preventing the hastening of the progression.

24. The combination with a road intersection, of an alternating stop and go trafiic signal and switch means operative in recurrent cycles having a normal period to periodically change the signal at normally regular intervals, said signal being adapted to give a stop indication along one of the intersecting roadways at the same time that it indicates go along the other of the intersecting roadways, vehicle-controlled means for temporarily shortening the normal operating period of the switch means, and means for efiecting restoration of the normal period of the operation of said switch means with each change of said signal.

ARTHUR AYLING BLUE. 

